Passover is a time to up the ante on keeping kosher, no matter where you are holding. Even those who do not keep kosher throughout the year can be seen putting away bread and pasta for a week and eating only matzah. Perhaps one reason for this is that Passover is a time for family, and it is during Passover that we reconnect with the traditions of our ancestors. Therefore, most Jews have some interest in what makes food kosher for Passover.
Basically, food is kosher for Passover if it doesn’t contain any products, such as yeast, that can make dough rise. Even foods made with flour that are not “puffed up” such as pasta, are still avoided, because the regular flour produces some type of leavening. Those who are careful to keep kosher for Pesach avoid flour and flour products.
However, for those who love cakes, cookies and even a bagel every morning need not feel deprived during Passover; there are ways to use matzah flour to make sponge cakes and other kosher for Passover goodies. The reason matzah balls, the classic Jewish dumpling for soup, were invented was to have something to put in soup over Passover.
However, there are many families who eat matzah balls all year round except on Passover. Haredi, or ultra-Orthodox families avoid what is called gebrocks, or any food made with wet matzah flour, on Passover. The reasoning behind this stringency is they haredim feel that water added to matzah flour might have a very slight chance of creating leavening. (most of these haredim, however, would not say that gebrocks are “not kosher” but that they avoid eating them, just to be on the safe side.)
Sephardic Jews from Middle Eastern countries, such as Iran and Morocco, and many Jews who currently live in the Land of Israel, eat kitniot, or legumes on Passover. These include beans, peanuts and other products. Ashkenazic Jews from Eastern Europe do not eat these foods on Passover.
Whatever “kosher for Passover” means to you, the Chassidic masters say that every detail in one’s observance during these days, whether it is some extra scrubbing for leavening before the holiday, or an extra stringency in keeping kosher, creates angels above which will plead one’s case in the Heavenly Court.